import {
  document,
	window,
	HTMLCanvasElement,
	requestAnimationFrame,
	cancelAnimationFrame,
core,
	Event,
  Event0
} from "dhtml-weixin"
import * as THREE from './three/Three';
import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
import { OrbitControls0 } from 'three/addons/controls/OrbitControls0.js';
import { ImprovedNoise } from './three/addons/math/ImprovedNoise.js';

import { GUI } from 'three/addons/libs/lil-gui.module.min.js';
import WebGL from 'three/addons/capabilities/WebGL.js';
var requestId
Page({
  onShareAppMessage(){
    return getApp().onShare()
  },
  onShareTimeline(){
     return {title:"ThreeX 2.0"}
  },
	onUnload() {
		cancelAnimationFrame(requestId, this.canvas)
		this.worker && this.worker.terminate()
if(this.canvas) this.canvas = null
		setTimeout(() => {
			if (this.renderer instanceof THREE.WebGLRenderer) {
				this.renderer.dispose()
				this.renderer.forceContextLoss()
				this.renderer.context = null
				this.renderer.domElement = null
				this.renderer = null
			}
		}, 0)
	},
  webgl_touch(e){
		const web_e = (window.platform=="devtools"?Event:Event0).fix(e)
		this.canvas.dispatchEvent(web_e)
  },
  onLoad() {
		document.createElementAsync("canvas", "webgl2").then(canvas => {
      this.canvas = canvas
      this.body_load(canvas).then()
    })
  },
  async body_load(canvas3d) {

  if ( WebGL.isWebGL2Available() === false ) {

    document.body.appendChild( WebGL.getWebGL2ErrorMessage() );

  }

  const INITIAL_CLOUD_SIZE = 128;

  let renderer, scene, camera;
  let mesh;
  let prevTime = performance.now();
  let cloudTexture = null;

  await init();
  animate();

  function generateCloudTexture( size, scaleFactor = 1.0 ) {

    const data = new Uint8Array( size * size * size );
    const scale = scaleFactor * 10.0 / size;

    let i = 0;
    const perlin = new ImprovedNoise();
    const vector = new THREE.Vector3();

    for ( let z = 0; z < size; z ++ ) {

      for ( let y = 0; y < size; y ++ ) {

        for ( let x = 0; x < size; x ++ ) {

          const dist = vector.set( x, y, z ).subScalar( size / 2 ).divideScalar( size ).length();
          const fadingFactor = ( 1.0 - dist ) * ( 1.0 - dist );
          data[ i ] = ( 128 + 128 * perlin.noise( x * scale / 1.5, y * scale, z * scale / 1.5 ) ) * fadingFactor;

          i ++;

        }

      }

    }

    return new THREE.Data3DTexture( data, size, size, size );

  }

 async function init() {

    renderer = new THREE.WebGLRenderer();
    renderer.setPixelRatio( window.devicePixelRatio );
    renderer.setSize( window.innerWidth, window.innerHeight );
    document.body.appendChild( renderer.domElement );

    scene = new THREE.Scene();

    camera = new THREE.PerspectiveCamera( 60, window.innerWidth / window.innerHeight, 0.1, 100 );
    camera.position.set( 0, 0, 1.5 );

    new (window.platform=="devtools"?OrbitControls:OrbitControls0)( camera, renderer.domElement );

    // Sky

    const canvas = document.createElement( 'canvas' );
    canvas.width = 1;
    canvas.height = 32;

    const context = canvas.getContext( '2d' );
    const gradient = context.createLinearGradient( 0, 0, 0, 32 );
    gradient.addColorStop( 0.0, '#014a84' );
    gradient.addColorStop( 0.5, '#0561a0' );
    gradient.addColorStop( 1.0, '#437ab6' );
    context.fillStyle = gradient;
    context.fillRect( 0, 0, 1, 32 );

    const skyMap = new THREE.CanvasTexture(await core.Canvas.fix(canvas3d,canvas ));
    skyMap.colorSpace = THREE.SRGBColorSpace;

    const sky = new THREE.Mesh(
      new THREE.SphereGeometry( 10 ),
      new THREE.MeshBasicMaterial( { map: skyMap, side: THREE.BackSide } )
    );
    scene.add( sky );

    // Texture

    const texture = new THREE.Data3DTexture(
      new Uint8Array( INITIAL_CLOUD_SIZE * INITIAL_CLOUD_SIZE * INITIAL_CLOUD_SIZE ).fill( 0 ),
      INITIAL_CLOUD_SIZE,
      INITIAL_CLOUD_SIZE,
      INITIAL_CLOUD_SIZE
    );
    texture.format = THREE.RedFormat;
    texture.minFilter = THREE.LinearFilter;
    texture.magFilter = THREE.LinearFilter;
    texture.unpackAlignment = 1;
    texture.needsUpdate = true;

    cloudTexture = texture;

    // Material

    const vertexShader = /* glsl */`
      in vec3 position;

      uniform mat4 modelMatrix;
      uniform mat4 modelViewMatrix;
      uniform mat4 projectionMatrix;
      uniform vec3 cameraPos;

      out vec3 vOrigin;
      out vec3 vDirection;

      void main() {
        vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );

        vOrigin = vec3( inverse( modelMatrix ) * vec4( cameraPos, 1.0 ) ).xyz;
        vDirection = position - vOrigin;

        gl_Position = projectionMatrix * mvPosition;
      }
    `;

    const fragmentShader = /* glsl */`
      precision highp float;
      precision highp sampler3D;

      uniform mat4 modelViewMatrix;
      uniform mat4 projectionMatrix;

      in vec3 vOrigin;
      in vec3 vDirection;

      out vec4 color;

      uniform vec3 base;
      uniform sampler3D map;

      uniform float threshold;
      uniform float range;
      uniform float opacity;
      uniform float steps;
      uniform float frame;

      uint wang_hash(uint seed)
      {
          seed = (seed ^ 61u) ^ (seed >> 16u);
          seed *= 9u;
          seed = seed ^ (seed >> 4u);
          seed *= 0x27d4eb2du;
          seed = seed ^ (seed >> 15u);
          return seed;
      }

      float randomFloat(inout uint seed)
      {
          return float(wang_hash(seed)) / 4294967296.;
      }

      vec2 hitBox( vec3 orig, vec3 dir ) {
        const vec3 box_min = vec3( - 0.5 );
        const vec3 box_max = vec3( 0.5 );
        vec3 inv_dir = 1.0 / dir;
        vec3 tmin_tmp = ( box_min - orig ) * inv_dir;
        vec3 tmax_tmp = ( box_max - orig ) * inv_dir;
        vec3 tmin = min( tmin_tmp, tmax_tmp );
        vec3 tmax = max( tmin_tmp, tmax_tmp );
        float t0 = max( tmin.x, max( tmin.y, tmin.z ) );
        float t1 = min( tmax.x, min( tmax.y, tmax.z ) );
        return vec2( t0, t1 );
      }

      float sample1( vec3 p ) {
        return texture( map, p ).r;
      }

      float shading( vec3 coord ) {
        float step = 0.01;
        return sample1( coord + vec3( - step ) ) - sample1( coord + vec3( step ) );
      }

      vec4 linearToSRGB( in vec4 value ) {
        return vec4( mix( pow( value.rgb, vec3( 0.41666 ) ) * 1.055 - vec3( 0.055 ), value.rgb * 12.92, vec3( lessThanEqual( value.rgb, vec3( 0.0031308 ) ) ) ), value.a );
      }

      void main(){
        vec3 rayDir = normalize( vDirection );
        vec2 bounds = hitBox( vOrigin, rayDir );

        if ( bounds.x > bounds.y ) discard;

        bounds.x = max( bounds.x, 0.0 );

        vec3 p = vOrigin + bounds.x * rayDir;
        vec3 inc = 1.0 / abs( rayDir );
        float delta = min( inc.x, min( inc.y, inc.z ) );
        delta /= steps;

        // Jitter

        // Nice little seed from
        // https://blog.demofox.org/2020/05/25/casual-shadertoy-path-tracing-1-basic-camera-diffuse-emissive/
        uint seed = uint( gl_FragCoord.x ) * uint( 1973 ) + uint( gl_FragCoord.y ) * uint( 9277 ) + uint( frame ) * uint( 26699 );
        vec3 size = vec3( textureSize( map, 0 ) );
        float randNum = randomFloat( seed ) * 2.0 - 1.0;
        p += rayDir * randNum * ( 1.0 / size );

        //

        vec4 ac = vec4( base, 0.0 );

        for ( float t = bounds.x; t < bounds.y; t += delta ) {

          float d = sample1( p + 0.5 );

          d = smoothstep( threshold - range, threshold + range, d ) * opacity;

          float col = shading( p + 0.5 ) * 3.0 + ( ( p.x + p.y ) * 0.25 ) + 0.2;

          ac.rgb += ( 1.0 - ac.a ) * d * col;

          ac.a += ( 1.0 - ac.a ) * d;

          if ( ac.a >= 0.95 ) break;

          p += rayDir * delta;

        }

        color = linearToSRGB( ac );

        if ( color.a == 0.0 ) discard;

      }
    `;

    const geometry = new THREE.BoxGeometry( 1, 1, 1 );
    const material = new THREE.RawShaderMaterial( {
      glslVersion: THREE.GLSL3,
      uniforms: {
        base: { value: new THREE.Color( 0x798aa0 ) },
        map: { value: texture },
        cameraPos: { value: new THREE.Vector3() },
        threshold: { value: 0.25 },
        opacity: { value: 0.25 },
        range: { value: 0.1 },
        steps: { value: 100 },
        frame: { value: 0 }
      },
      vertexShader,
      fragmentShader,
      side: THREE.BackSide,
      transparent: true
    } );

    mesh = new THREE.Mesh( geometry, material );
    scene.add( mesh );

    //

    const parameters = {
      threshold: 0.25,
      opacity: 0.25,
      range: 0.1,
      steps: 100
    };

    function update() {

      material.uniforms.threshold.value = parameters.threshold;
      material.uniforms.opacity.value = parameters.opacity;
      material.uniforms.range.value = parameters.range;
      material.uniforms.steps.value = parameters.steps;

    }

    const gui = new GUI();
    gui.add( parameters, 'threshold', 0, 1, 0.01 ).onChange( update );
    gui.add( parameters, 'opacity', 0, 1, 0.01 ).onChange( update );
    gui.add( parameters, 'range', 0, 1, 0.01 ).onChange( update );
    gui.add( parameters, 'steps', 0, 200, 1 ).onChange( update );

    window.addEventListener( 'resize', onWindowResize );

  }

  function onWindowResize() {

    camera.aspect = window.innerWidth / window.innerHeight;
    camera.updateProjectionMatrix();

    renderer.setSize( window.innerWidth, window.innerHeight );

  }

  let curr = 0;
  const countPerRow = 4;
  const countPerSlice = countPerRow * countPerRow;
  const sliceCount = 4;
  const totalCount = sliceCount * countPerSlice;
  const margins = 8;

  const perElementPaddedSize = ( INITIAL_CLOUD_SIZE - margins ) / countPerRow;
  const perElementSize = Math.floor( ( INITIAL_CLOUD_SIZE - 1 ) / countPerRow );

  function animate() {

    requestId = requestAnimationFrame( animate );

    const time = performance.now();
    if ( time - prevTime > 1500.0 && curr < totalCount ) {

      const position = new THREE.Vector3(
        Math.floor( curr % countPerRow ) * perElementSize + margins * 0.5,
        ( Math.floor( ( ( curr % countPerSlice ) / countPerRow ) ) ) * perElementSize + margins * 0.5,
        Math.floor( curr / countPerSlice ) * perElementSize + margins * 0.5
      ).floor();

      const maxDimension = perElementPaddedSize - 1;
      const box = new THREE.Box3( new THREE.Vector3( 0, 0, 0 ), new THREE.Vector3( maxDimension, maxDimension, maxDimension ) );
      const scaleFactor = ( Math.random() + 0.5 ) * 0.5;
      const source = generateCloudTexture( perElementPaddedSize, scaleFactor );

      renderer.copyTextureToTexture3D( box, position, source, cloudTexture );

      prevTime = time;

      curr ++;

    }

    mesh.material.uniforms.cameraPos.value.copy( camera.position );
    // mesh.rotation.y = - performance.now() / 7500;

    mesh.material.uniforms.frame.value ++;

    renderer.render( scene, camera );

  }
  }
})